The goals of this project are to improve our understanddng of membrane function at a molecular level through analyses of the specificities of interactions among the principal membrane components. Phosphatidylcholine analogs will be synthesized having variations in the structure of the polar region. The interactions of these analogs with the D-beta-hydroxybutyrate dehydrogenase calcium pump protein, phospholipid exchange protein, and cholesterol will be studied by biophysical techniques.